The present invention relates to a scroll fluid machine with a silencer to reduce as much as possible noise caused by a gas compressed and discharged during operation.
In a scroll fluid machine as shown in FIG. 3, an orbiting scroll is eccentrically revolved in a housing, so that a gas sucked on the outer circumference of the housing is guided into a compression chamber between the orbiting scroll and a fixed scroll, compressed towards a center and discharged from the center.
The housing 21 that has a compression chamber 22 comprises a casing 23 and a cover 24 and has a sucking inlet 25 on the outer circumference. The casing 23 and the cover 24 comprise fixed end plates 26,27 surrounding the compression chamber 22. On the inner surface towards the compression chamber 22, spiral fixed wraps 28,29 are provided respectively to form fixed scrolls 30,31.
Between fixed end plates 26 and 27, the orbiting scroll 32 is revolved around an axis of the compression chamber 22.
The orbiting scroll 32 has an orbiting end plate 33 which has orbiting wraps 34,35 engaged with the fixed wraps 28,29. The orbiting scroll 32 is pivotally mounted around an eccentric axial portion 39 of a driving shaft 38 via bearings 36,37.
The orbiting end plate 33 is engaged with the fixed end plates 26,27 with a three known pin-crank-type self-rotation preventing devices (not shown). The orbiting end plate 33 is revolved with rotation of the driving shaft 38 in the compression chamber 22 to allow radial distance of a space between the fixed wraps 28,29 and the orbiting wraps 34,35 to vary.
In the vicinity of the center of the casing 23, there is formed in the fixed end plate. 27 an axial opening 43 the inner end of which opens near the center of the compression chamber 22 and the outer end of which is closed by a stopper 42.
In the fixed end plate 27, the opening 43 communicates with a radial discharge hole 44 which fits in a discharge joint 45 with a check valve at the outer end.
The driving shaft 28 is driven by a motor (not shown), and cooling fans 46,47 are mounted to the driving shaft 38 close to the casing 23 and the cover 24.
With rotation of the driving shaft 38, the orbiting scroll 32 is eccentrically revolved by the eccentric axial portion 39 while being engaged with the fixed scrolls 30,31. So a gas is sucked from the sucking inlet 25, compressed in the compression chamber 22, transferred toward the center and ultimately discharged via the opening 43, the discharge hole 43 and the discharge joint 45.
Sound of gas discharged from the discharge hole 44 and discharge joint 45 is greatly high, and a silencer 50 is mounted to an outlet of the discharge hole 44 or discharge joint 45. However, the silencer 50 protrudes axially or radially of the scroll fluid machine to increase a size of the scroll fluid machine and/or to involve difficulty in handling.